How to make a basket for straw pasteurisation

The corona measurements are having an effect all over the world. And although our urban mushroom farm is resilient to shocks, we had to adjust to the reality around us. One of those things was the sudden decline in coffee grounds. 

As you might know, our urban farm grows oyster mushrooms on coffee grounds. We collect this coffee at the office buildings where our customers are located. These buildings produce up to 1000 kilo of coffee grounds per month! 

With almost the entire working population of the Netherlands working from home and all the restaurants being closed, we ran out of coffee grounds for our substrate in a hearth beat. If we wanted to continue cultivating mushrooms, we had to adjust. We decided to start to make substrate from straw.

Straw needs to be pasteurised and the basket we used for that, we normally only use in workshops. After a few runs, it was exhausted, so we needed a new one. 

We decided to make the new basket a bit more firmer as we are going to use it more intensive the coming months. After step one, measuring, it was time to make a mold to build the basket around.

After that we had to bend aluminium strips around this shape and bolt them together. These strips form the basic strength of this basket.

Once we had the frame ready, we could work with the mesh. We used standard chicken mesh available in any hardware store. By wrapping it around the mold 4 times, we gave extra strength to the basket.

When we fixed the two together, all what was needed was a lid and some handles.

We are very pleased with the result and used it in substrate production immediately. This basket is larger and works much finer than our previous one. We can put a little over 12 kg of dry straw in it. This gives us about 56 kilo of wet straw. From this we make 14 x 4 kilo bags of substrate.

With two runs a day and 4 days a week we produce a little under 2 tons of substrate per month. A lot less then before corona on coffee, but for the time being this works for us. 

We also made a video of the building proces that you can see on our YouTube channel. Next to that we provide a free pdf file of the process of this build. You can download it here.

Do you work with straw? If so, how do you pasteurise it? Let us know in the comments below.